1. Technical Field
The present invention relates to a piezoelectric oscillator that is of the surface-mount type used in communication equipment and an electronic apparatus.
2. Related Art
Commonly, a piezoelectric oscillator such as a crystal oscillator provided with an electrical check terminal on a side surface of a package formed with a ceramic has been known. This electrical check terminal is a terminal connected with a crystal resonator element or an IC chip including an oscillation circuit and a memory circuit, and used for measuring oscillation frequency of the crystal resonator element, or writing temperature compensation data into the IC chip.
In recent years, downsizing of apparatuses has been rapidly progressed due to demand of improving portability of electronic apparatuses and communication equipment. Therefore, a piezoelectric oscillator as typified by a crystal oscillator used for those apparatuses is required to be reduced in size and height.
Along with the reduction in size and height of a crystal oscillator, a space to form an electrical check terminal on a package becomes limited. Therefore, a crystal oscillator having a structure to form an electrical check terminal on a bottom surface of the package is suggested as disclosed in JP-A-2005-268257 (FIGS. 2 and 3).
However, as a result of the reduction in size and height of a piezoelectric oscillator, a circuit element such as an IC chip accounts for a large portion of a package considering the size of the package. Therefore, an area to form an electrical check terminal on the bottom surface of the package becomes small. Further, when the size of an IC chip is larger than the package, an electrical check terminal cannot be formed on the bottom of the package.